while it was still stock, best hi-way was 20.7, under 65 MPH.
While on 30 mi commute, country roads was 16 mpg. Then added AFEstage 2 prodry, milage went up to 17,2-17.5.
Later added 4 in exhaust and DPtunes. only been short trips 3-10mi. hilly too 13-15mpg. Don't know about hi-way yet.
AFE added 1.2-1.5. don't know what Exhaust and DP Tunes difference is yet.